Huawei H12-831_V1.0 Exam With Confidence Using Practice Dumps

Comprehensive and Detailed In-Depth Explanation:

Step 1: Identify the Primary Path

The shortest OSPF cost to 10.0.3.3/32 from R1 is through R5:

R1 → R5 (Cost 10) → R3 (Cost 10) = Total Cost 20

The primary outbound interface from R1 to R5 is GE0/0/1.

Step 2: Identify the Backup Path (OSPF IP FRR & ECMP)

OSPF IP Fast Reroute (FRR) provides a backup next-hop in case the primary link (R1 → R5) fails.

A feasible backup path must have a cost equal to or close to the primary path, but it must avoid the same failure point.

Alternative Path Calculation:

Path 1 (R1 → R2 → R3)

R1 → R2 (Cost 10), R2 → R3 (Cost 10) → Total Cost = 20 ✅

Uses interface GE0/0/2 on R1.

Path 2 (R1 → R4 → R3)

R1 → R4 (Cost 10), R4 → R3 (Cost 10) → Total Cost = 20 ✅

Uses interface GE0/0/3 on R1.

Final Decision on the Backup Interface

Since both paths R1 → R2 → R3 and R1 → R4 → R3 have equal costs, either can be used for backup.

However, R1 → R2 → R3 shares a direct cost path with R5, meaning it may not be preferred as a full FRR backup.

The best backup outbound interface in this scenario is GE0/0/3 (R1 → R4 → R3).

Final Answer: ✅ C (GE0/0/3)

References:

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 – OSPF IP FRR (Fast Reroute) Mechanism

OSPF Equal-Cost Multi-Path (ECMP) and Backup Route Selection

OSPF Route Calculation and Best-Path Selection

Comprehensive and Detailed In-Depth Explanation:

1. Understanding the Network Setup

PE1 (Provider Edge 1) is the gateway for network 192.168.1.1/24.

PE2 (Provider Edge 2) is the gateway for network 192.168.2.1/24.

A cloud-based backbone connects PE1 and PE2.

To verify end-to-end communication, engineers need to check reachability between PE1 and PE2.

2. Evaluating Each Answer Option

Option A: "Configuring NQA on PE1 and PE2, with the destination address being the IP address of each other."

✅ Correct.

NQA (Network Quality Analysis) is a network testing tool that allows connectivity testing between two devices.

Configuring NQA between PE1 and PE2 will verify end-to-end reachability.

Option B: "On PE1 and PE2, checking whether the ARP table contains the ARP entry of the peer network segment."

❌ Incorrect.

ARP (Address Resolution Protocol) is only used for resolving MAC addresses within the same broadcast domain.

Since PE1 and PE2 are in different network segments (separated by a routed network), they will not have ARP entries for each other.

Instead, routing entries should be checked, not ARP.

Option C: "On PE1, using 192.168.1.1 as the source address to ping 192.168.2.1."

✅ Correct.

A simple ping test using the source address of PE1 (192.168.1.1) to reach PE2 (192.168.2.1) will verify whether routing between the two locations is functional.

Option D: "On PE1 and PE2, checking whether there are routes to each other’s network segment in the routing tables."

✅ Correct.

If routing is not configured correctly, PE1 and PE2 will not know how to reach each other.

Checking the routing table ensures that both PEs have the correct next-hop information.

Final Answer:

✅ A, C, and D are correct.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Using NQA for Network Connectivity Testing

Verifying Routing Table Entries for Inter-Network Communication

Understanding ARP and Its Limitations in Routed Networks